Yes, show us someone winning with them consistently in the ranked/meta, and THEN you can say they are viable. Talking theory is just that, talking theory.
Too bad most fairies are ranged. Conclave Warden, Nectar Fairy (but wouldn't you use them as healers first?) and Wisp. Horn of K'thir only works with melee. Battle Leader is on Vashal Cavalier. He's the only KF with it. (This might have already been answered)
I didn't read this thread...but i'm going to claim fairies are a joke because the developers aren't German enough. German fairies are scary Bane Shift.
I detect a distinct inference that such soul eating is NOT a good thing. And yet, in Pox, that would be most welcome.